Microlithography can be used for the production of microstructured components such as for example integrated circuits or LCDs. The microlithography process is generally carried out in what is referred to as a projection exposure apparatus which has an illumination system and a projection objective. The image of a mask is typically illuminated by the illumination system (=reticle) and is typically projected by the projection objective on to a substrate (for example a silicon wafer) which is typically coated with a light-sensitive layer (for example photoresist) and arranged in the image plane of the projection objective in order to transfer the mask structure on to the light-sensitive coating on the substrate.